Why it has taken this much time to develop COVID vaccine?

Vaccines have historically taken two to five years to develop. But with a global effort, and learning from past efforts to develop coronavirus vaccines, researchers could potentially develop a vaccine in a much shorter time. The challenges that faced by the clinical institutions in developing vaccines are:

• The full RNA sequence of the virus – now known as SARS-CoV-2 rather than COVID-19, which refers to the disease itself.
• Difficulty in developing and validating the right biological model for the virus. This will be an animal model that gives us clues to how the coronavirus might behave in humans.
• Another challenge is manufacturing proteins from the virus needed to develop potential vaccines. These proteins are specially designed to elicit an immune response when administered, allowing a person's immune system to protect against future infection. Fortunately, recent advances in understanding viral proteins, their structure and functions, has allowed this work to progress around the world at considerable speed.

When these two vaccinations will reach to all?

The first recipients of the vaccine will be 30 million (3 crores) workers in the forefront of India’s battle against the novel coronavirus, including 1 crore healthcare workers and 2 crore frontline workers  Frontline essential workers such as firefighters, police officers, corrections officers, food and agricultural workers, United States Postal Service workers, manufacturing workers, grocery store workers, public transit workers, and those who work in the educational sector (teachers, support staff, and daycare workers) which will be administered to them for free. People aged 75 years and older because they are at high risk of hospitalization, illness, and death from COVID-19. People aged 75 years and older who are also residents of long-term care facilities should be offered vaccination in Phase 1a. Also receiving the vaccine in the first phase will be a third priority group – consisting of some 27 crore persons above age 50, and persons below age 50, but with associated comorbidities.

The government aims to complete the first phase of vaccinations by August 2021. The timelines for the rest of the population are not known as yet. However, it is not as though the rest of the population will have to wait until the first phase of vaccination is complete. Other groups will begin to be inoculated simultaneously after some weeks or months.

Covaxin is based on a highly purified and inactivated two-dose Sars-Cov-2 vaccine manufactured in a vero cell manufacturing platform. The company claims this platform has an “excellent safety track record” of more than 300 million doses. It is the traditional vaccine technology that uses an inactivated virus to prime our immune response against the pathogen. The advantage is that it is time-tested, and when a whole virus is used, theoretically it should induce an immune response for variant strains. However, we do not know the efficacy of Covaxin yet.

The Oxford-AstraZeneca vaccine, on the other hand, uses a chimpanzee adenovirus (common cold virus) to deliver the genetic material of a pathogen into cells. This creates an immune response against the Sars-CoV-2 virus.

Bharat Biotech added Covaxin had been evaluated in approximately 1,000 subjects in the Phase 1 and Phase 2 clinical trials and the data has been accepted in international peer-reviewed scientific journals. The vaccine is now in the middle of a 26,000 volunteer Phase 3 efficacy study, the largest such trial ever conducted for any vaccine in India.

Who approved this vaccine for emergency use?

India's first vaccine against COVID-19 is approved by the Drug Controller General of India (DCGI) which us the great development for us. Drugs Controller General of India (DCGI) is the head of the department of the Central Drugs Standard Control Organization of the Government of India responsible for approval of licences of specified categories of drugs such as blood and blood products, IV fluids, vaccines, and sera in India. Drugs Controller General of India comes under the Ministry of Health & Family Welfare. V. G. Somali is the Drug Controller General of India for now.

The function of the DCGI is:

• Acting as an appellate authority in case of any dispute regarding the quality of drugs.
• Preparation and maintenance of national reference standard.
• To bring about the uniformity in the enforcement of the Drugs and Cosmetics Act.
• Training of Drug Analysts deputed by State Drug Control Laboratories and other Institutions
• Analysis of Cosmetics received as survey samples from CDSCO (central drug standard control organisation)

On Sunday, 3rd January 2021, DCGI gives formal approval for the coronavirus vaccines of Oxford-AstraZeneca, manufactured by the Serum Institute, and Bharat Biotech, saying they will be administered in two dosages each.
This approval was given based on recommendations submitted by a coronavirus subject expert committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO).

How the vaccines go through testing?

All vaccines aim for the same goal: exposing the body’s immune system to protein or carbohydrate fragments, or antigens, displayed by a virus or other pathogen. If all goes as planned, “memory cells” within the immune system remember this introduction. If the vaccinated person is later exposed to the actual virus, these cells enable the immune system to react quickly, suppressing the disease or reducing its severity.  But the vaccines differ only at one place,  in how they present those antigens. Some vaccines, such as ones against measles and polio, use the entire virus that has been either killed or damaged so that it no longer causes disease. Other vaccines extract the viral gene that codes for the desired antigen and inserts it into another, the less harmful virus that is then delivered to the patient (the recently approved vaccine for Ebola is a case in point). Still, others use bacteria or yeast to manufacture the antigen in fermentation vats. The antigen can then be injected directly, as in the hepatitis B vaccine, or used to build empty shells of viruses that lack genetic material, as in the vaccine against human papillomavirus.

Newer, more experimental vaccines deliver not the antigen itself but the genetic material that codes for it, either as RNA or DNA, usually encapsulated in a fatty membrane. This enters the body’s cells and directs them to make the relevant protein themselves to trigger the immune response. Such vaccines could be quicker to create because genetic material is easier to mass-produce than proteins are. But RNA and DNA vaccines are so new that none have yet been approved for use by the general public. Like all medicines, after vaccines are tested in experimental animals, they go through three phases of testing in people. First, a few healthy volunteers receive the vaccine: This Phase 1 trial tests for safety and gives a rough idea of how much vaccine is needed. After that, researchers work out dosing and safety in more detail in a somewhat larger group — the Phase 2 trial. Phase 3 trial is the most time-consuming step I testing because researchers have to wait for enough participants to be exposed to a virus naturally.